Geocaching has become a popular family activity

Aurora Stevens, 7 (left), and her sister Nayely, 6, open the geocache they just found and read the coordinates written on a scrap of paper to find the next location in their treasure hunt. Mom Wendy Stevens looks on as dad James Stevens prepares to enter the new latitude and longitude into his hand-held GPS unit.

Photo By Michelle Koidin Jaffee/San Antonio Express-News

Aurora and Nayely Stevens search for the next geocache in Olmos Basin Park. With their parents, teachers Wendy and James Stevens, the girls go geocaching almost every weekend.

Photo By Michelle Koidin Jaffee/San Antonio Express-News

Wendy Stevens enters coordinates of the next hidden geocache into her GPS unit, and the family is off on the hunt for another “treasure.”

Photo By Michelle Koidin Jaffee/San Antonio Express-News

Nayely Stevens uses a hand-held GPS device to search for the next location of a hidden geocache in Olmos Basin Park.

Photo By Michelle Koidin Jaffee/San Antonio Express-News

The Stevens family discovers where to go next when they open one geocache container and remove a slip of paper that provides coordinates for the next find.

Photo By Michelle Koidin Jaffee/San Antonio Express-News

Aurora Stevens discovers a geocache in the hole of a tree. After writing her name on a scroll, she puts the tube back where she found it.

Photo By Michelle Koidin Jaffee/San Antonio Express-News

Nayely Stevens, 6, carries a just-found geocache to a clearing in Olmos Basin Park as her sister, 7-year-old Aurora, follows.

Photo By Michelle Koidin Jaffee/San Antonio Express-News

Nayely Stevens, 6, uses a hand-held GPS device to search for the location of the next geocache during her family's outing in Olmos Basin Park.

More Information

• Using a GPS device or smartphone, players navigate to a specific set of GPS coordinates, such as N 45° 17.460 W 122° 24.800 (the coordinates of the first-ever geocache), to locate hidden containers. Experiences then can be shared online.

• Rules include: If you take something from the geocache, leave something of equal or greater value.

• Geocaches can range in size from a 35 mm film canister to a 20-liter bucket.

• A “Trackable” is a geocaching game piece. Found in geocaches, the coinlike objects are etched with a unique code that can be used to log the trackable’s movements on geocaching.com as it travels the world.

Source: geocaching.com

Just about every weekend, the Stevens family heads into the woods in search of treasure.

Well, maybe not what you would call “treasure” — plastic trinkets, keychains, collectors' coins and the like. But it's the thrill of a game called geocaching, using a GPS unit or smartphone app to locate hidden canisters containing the items that are stashed in trees, under leaves and beside logs.

Sometimes, the canisters are as small as a pill bottle wrapped in camouflage duct tape and containing a scroll to sign your name and the date. Other times, they're as big as a shoe box or bucket.

Mom Wendy Stevens, dad James and daughters Aurora, 7, and Nayely, 6, enjoy the activity so much that they often take a longer route home from school in order to find a geocache along the way.

“It's not about what's in the box,” says James, who teaches aquatic science and physics at Marshall High School. “It's about finding the box.”

Since May 2000, when action by the government suddenly opened GPS accuracy to civilians, and then the next day, when a computer consultant hid the first-ever geocache in the woods near Beavercreek, Ore., the high-tech scavenger hunt has taken off in popularity.

Across the United States and the world, hobbyists began hiding geocaches in state parks, in neighborhoods — even in front of places like Home Depot and Target — and then logging the GPS coordinates on geocaching.com for others to find. The website recently published the location of its 2,030,461st geocache, and the number is constantly growing.

In San Antonio, there are geocaches hidden all over the city, including one at Woodlawn Lake accessible only by canoe or kayak.

Seizing the opportunity to get the attention of today's electronically-connected kids and entice them to visit state parks, park rangers are pitching geocaching as the perfect bridge activity between technology and nature.

There are more than 800 geocaches inside Texas state parks.

“All the sudden, the outdoors becomes a treasure hunt instead of just a nature hike,” says Robert Owen, coordinator of the Texas Outdoor Family Program, which provides ranger-led camping trips and activities — including geocaching — in Texas state parks.

Rangers see these camping trips as an ideal chance to introduce the game to families.

“It blends the technology we use every day with nature,” says Owen. On any hike, he says, there's always plenty to see. But with geocaching, “you know that at your destination you're going to have a game as well. It makes reaching your destination a little more exciting.”

He believes the game is a natural for kids who love video games.

“It's usually the parents I have to explain the GPS unit to,” he says. “Kids — they're on their way after one explanation.”

Geocaching has become increasingly accessible with smartphones; there are free apps for Android and iPhone and a $10 “official app” from geocaching.com that is much more comprehensive and shows all caches close to your immediate location.

Like any sport, there are rules for the game. For example, to place a new geocache in a Texas state park, a permit must be downloaded and brought to the park superintendent.

To keep the game going, you must put a just-found geocache back exactly where you found it.

And if you remove a trinket from a geocache, you must replace it with an object of equal or greater value.

From his geocaching adventures, 6-year-old Eden Hassard has amassed a collection of distinctive patches that now adorn the vest he wears on outings.

His grandparents, Mary and Roger Hassard, started geocaching three years ago in an effort to find a fun activity to do with the boy, who spends every other weekend with them.

Eden, who is a kindergartner at Somerset Elementary, now has 740 finds.

“You oughta see his eyes when he opens it,” his grandpa says.

On a recent Saturday, the Stevens family headed to Olmos Basin Park. Their first GPS coordinates led them to a spot behind a soccer field covered in poison ivy. They wisely decided to skip that one.

But during what turned into a 2½-hour hike in the park, they found three other geocaches, two in the dense woods beside U.S. 281 with cars whizzing by.

Geocaching, says James Stevens, teaches patience, persistence and the skill of observation. It also encourages his girls — a second-grader and a kindergartner at Vineyard Ranch Elementary School — to cooperate on the shared mission.

“When we're doing more active stuff, they don't have as much time to fight,” he says with a grin.

Reaching into the hole in a tree and pulling out one geocache, 7-year-old Aurora breaks into a huge smile and bows her head wildly in celebration.

It was the family's 523rd cache, and the girls show no sign of slowing down.

With geocaching, says 6-year-old Nayely, “I can go out with my family and have fun.”